The present invention relates to xanthine and phenazone-acesulfame-H complexes or adducts having improved taste, process for their preparation, their use and pharmaceuticals comprising such compounds.
Xanthine derivatives, for example propentofylline and pentoxifylline are used as pharmaceuticals in human and veterinary medicine. Corresponding pharmaceuticals are available on the market. 
Propentofylline has been used for a number of years in geriatrics in dogs to improve the flow properties of blood in the cerebral and peripheral area. In human medicine, propentofylline is in the advanced stage of clinical development for long-term treatment of patients having Alzheimer's disease and vascular dementia. In clinical studies on humans, propentofylline improved cognitive functions and global functions and activities of everyday life in patients having Alzheimer's disease and vascular dementia.
DE-A 198 34 604 and WO-A 00/07541 also describe the use of propentofylline for treating erectile dysfunctions.
Pentoxifylline has been used for a long time as a pharmaceutical under various trade names, for example Trental®, Azupentat® to improve hemodynamics in human patients suffering from cerebral, peripheral arterial and arteriovenous circulation disorders.
Propentofylline and pentoxifylline and other xanthines and xanthine derivatives, however, have an unpleasantly bitter taste, so that these compounds as active ingredients in pharmaceuticals, because of the unpleasant taste, can cause an aversion in many patients, in particular because these pharmaceuticals have to be taken sometimes for years.
1-Phenyl-2,3-dimethyl-3-pyrazolin-5-one derivatives from the class of substances of phenazones, for example phenazone (Dentigoa® N, Eu-Med mono®) itself, propylphenazone (Arantil P®; R=—CH(CH3)2), aminophenazone (Pyramidon®; R=—N(CH3)2) and metamizole (Novalgin®; R=—NCH3—CH2—SO3Na) have analgesic and antipyretic effects. Phenazones are known active pharmaceutical ingredients and taste very bitter, and masking this unpleasant taste would be desirable, especially if pharmaceuticals which comprise these active ingredients must be taken repeatedly or over a relatively long period. 
DE-A 1 242 622, EP-A 0 046 506, WO-A 99/04822 and WO-A 00/12067 describe compounds of sweetener and active pharmaceutical ingredients having an improved taste, where in each case the sweetener and the active compound are present in a molar ratio of 1:1. These are acid addition salts or ionic salt compounds in which the sweetener molecule is present as anion. These salts are prepared by an acid-base reaction, the sweetener being reacted as acid with the basic active compound.
It was an object of the present invention to provide xanthine derivatives, for example propentofylline and pentoxifylline, and phenazone derivatives, for example phenazone, in a form which enables their simple use in the preparation of, for example, pharmaceuticals or other preparations, and in which the bitter taste of these active compounds is masked or suppressed. As a result the acceptance of such pharmaceuticals in human and veterinary medicine can be significantly increased and thus the success of therapy, in particular in the case of frequent or long-term intake, can be significantly increased.